Screw driver



`lune 7, 1932. Q EDSTRQM ,862,470

SCREW DRIVER Filed June 26, 1931 INVENTOR.'

H25 ATTORNEYS.

Patented June 7, 1932 ATENT OFFICE GUS EDSTROM, F MERRILL, WISCONSINSCREW DRIVER Application` led June 26, 1931,

This inventionlrelates tocertain novel improvements in screw drivers,and has for its principal object the provision of an improvedconstruction of this character which will be highly efcient in use andeconomical in manufacture.

It is the principal object of this invention to provide an improvedscrew driver, and, more specically a screw driver in which the 1Hdriving shank may be continuously rotated in one direction, eitherclockwise or counterclockwise, by an oscillatingclockwise-counter-clockwise motion of the driving means, thereby toeliminate the lost motion'associated l" with the back up movement inscrew drivers in which the shank is driven only when the driving meansare being rotated in the direc-A tion in which the shank is beingrotated.

It is another object of the invention to 2 provide unique means forreadily changing the direction in which the shank will be rotated by theoscillating clockwise-counterclockwise motion imparted to the drivingmeans, and to construct these means in such a manner that the screwdriver may be readily changed from what will be termed hereinafterrigid7 movement, that is movement of the shank and driving means in thesame direction, to either right or left turn rotation of the shank byback and forth movement of the driving means.

Other objects will appear hereinafter.

The invention consists in the novel combination and arrangement of partsto be hereinafter described and claimed.

The invention will be best understood by reference to the accompanyingdrawing showing the preferred form of construction, and in which:

Fig. 1 is an elevational view of the invention assembled;

Fig. 2 is a longitudinal sectional view on line 2--2 in Fig. 4, showingthe operating parts set for clockwise rotation of the shank;

Fig. 3 is a longitudinal sectional view showing the operating parts setfor counterclockwise rotation of the shank;

Fig. 4 is a top plan view, partly in sect-ion on line 4 4 in Fig. 3 i

Serial N0. 547,108.

Fig. 5 is a sectional View on line 5 5 in Fig. 2;

Fig. V6 is a sectional view on line 6-6 in Fig. 2; and

Fig. 7 is a sectional view'ion line 7-7 in Fig. 2.

1n the drawing, which illustrates a practical and preferred embodimentof the invention, the externally threaded shank of the screw driver isindicated at 10 and has arranged thereon a chuck 11 of conventionaldesign, carrying a removable vloit or driver 12. The shank 10 forms oneend portion of a shaft 13 on which is mounted, adjacent the shank, andby a pintle 14, a collar 15 that includes a segment 15 in which isprovided a slot 16. Formed in the shaft 13 and extending longitudinallyor axially thereof, is a keyway or groove 17 in which is slidablymounted a bar 18, the front end of which is notched to provide spacedapart tapered cam faces 19 and .19 which are adapted to be abutted bythe periphery of a cam 2O that is loosely mounted on the pintle 14 andprovided with a segment of finger-gripping teeth 21. Provided in thefront end portion of the slidable bar or rod 18 is a slot 22 throughwhich the pintle 14 projects.

From the above description, therefore, it will now be seen that the baror rod 18 may be slid in the groove 17, for reasons that will becomeapparent as the description proceeds, by placing the thumb on the teeth21 and manipulating the cam wheel 2O against the face 19 of the cam formovement of the bar 18 in one direction, and against cam face 19 formovement of the bar 18 in the opposite direction, while when the camwheel 2O is disposed as in Fig. 1, the bar 18 is held immovable.

Spaced apart upon and fixed to the shaft 13 are similar collars 23 and24, each of which is provided with diametrically opposed notches 25, andthese collars 23 and 24 are provided with aligned slots 26 through whichthe slidable bar 18 passes.

Provided in each of the collars 23 and 24 are diametrically opposedslots 27 (Fig. 7). In the slots 27 in collar 24 a pair of latching dogs28 and 28 are mounted and similar dogs extends an arm 31 of a link32-32, each of the links 32 and 32 having one end 33 (Fig. 7) disposedin a recess 34 in the slide bar 18 and the other end 34a (Fig. 4) hookedunder a pin 35 that protrudes from the collar (23 'l or 24).

Associated with each of the collars 23 and 24 is a substantiallysemi-circular spring 36 and each of which springs is disposed in one ofthe notches 25 in the collars, and the ends 37 of these springs aredirected through slots 38 in the latching dogs 28 and 28, and 29 and 29.The springs 36 tend, therefore, to spread the pairs of dogs 28 and 28and 29 and 29 apart and to lift them out of the slots 27 in the collars23 and 24.

rtpertured for the passage therethrough of the shaft 13 is a block 39which is fixed to the immovable sleeve 43 at 44 and which floats onshaft 13. This block 39 carries diametrically opposed studs 40 on eachof which is rotatably mounted a bevel gear 42. One end of the stationarysleeve 43 is attached to this block 39 by screw 44, and the other end ofthe stationary sleeve 43 is attached, by screw 45, to a block 4G thatrides loosely on the shaft 13 and is slotted for the passagetherethrough of the slide bar 18.

T he sleeve or hand grip 47 has its rear end attached, by screw 48, to abearing block 49 in which the rear end of shaft 13 is ournaled, whilethe front end of the sleeve 47 is attached, by screw 50, to a bevel gear51 that is rotatably mounted on shaft 13 and meshes with the bevel gears42. The bevel gear 51 is provided with a ring of spaced latching fingers52 which extend over a part of the collar 24 and into the spaces betweenwhich the latching dogs 28 and 28 may be spread in a manner to beexplained hereinafter.

ln front of the bevel gears 42, meshing therewith, and rotatably mountedon the shaft 13, is a bevel gear 53 that is similar to gear 51 and thathas a ring of latching fin- 54 that are similar to the fingers 52. andinto the spaces between which fingers 54 the latching dogs 29 and 29 maybe spread by movement of the slide bar 18 in a manner to be describedpresently.

The latching dogs 29 and 29 have oppositely beveled edges 55 and 56(Fig. 6) and the dogs 28 and 28 are similarly constructed.

The operation of the invention is as follows: Assuming that the operatordesires to employ the device as a rigid screw driver and to drive theshaft 13, its shank 10 and bit 12 continuously in a right or left turn(elocle wise or counterclockwise rotation) by a similar movement ofsleeve 47, he then moves the cam wheel 2O into the position of Fig. 1

which will, acting through the slide bar 18, raise the links 32 in theslots 30, and allow the springs 3G to spread the latching dogs 28-28 and29-29 apart, thus disposing dogs 29 and 29 between fingers 54 and dogs28 and 28 between fingers 52. It is therefore readily apparent thatrotation then imparted to sleeve 47 will rotate the entire device as arigid unit since the gear 51 to which the sleeve 47 is attached, byscrew 50, cannot then be rotated independently of the shaft 13 to drivethe bevel gears 42 and its companion gear 53; this by reason of thestraight or noirbeveled edges 57 and 58 of dogs 29 and 29 andcorresponding edges on dogs 28 and 28 which will be abut-ted by thefingers 54 and when the motion of sleeve 47 is imparted to gear 51.

When it is desired to rotate shaft 13, its shank 10 and bit 12continuously in a right turn or clockwise rotation. as seen looking fromright to left in the drawing, the cam wheel 20 is moved into theposition of Fig. 2 which moves the slide bar 18 forward and raises thelinks 32 in slots 30 so that the dogs 28 and 29 are moved by springs 36into spaces between adjacent pairs of fingers 52 and 54, respectively,while withdrawing the dogs 28 and 29 into their respective slots 27 inthe collars 24 and 23 respectively, by means of links 32 which areeccentric with respect to links 32. The sleeve 43 being held in onehand, the to and fro, or oscillatory driving movement then imparted bythe operators other hand to sleeve 47 will be transmitted, through screw50 to gear 51, and as the gear 51 is rotated counterclockwise(lookingfrom right to left in the drawing) the fingers 52 will ride overthe beveled edge of dog 28, which is beveled in the opposite directionto the bevel 55 of dog 29, and motion will then be imparted by gear 51to gears 42, and gear 53. The gear 53, shaft 13, and bit 12 will thus berotated clockwise, since one of the fingers 54 will abut the edge 57 ofdog 29, imparting motion through the dog 29 to collar 23 and the shaft-13. l/'Vhen the operator reverses the movement of sleeve 47 and rotatessleeve 47 to the right, (clockwise as seen looking from right to left inthe drawing) the motion imparted by sleeve 47 to gear 51 will betransmitted through gears 42 to gear 53 which will then be rotatedcounterclockwise (looking from right to left in the drawing) and thefingers 54 will then ride over the beveled edge 55 of dog 29 while oneof the ngers 52 will abut the edge (corresponding to edge 57 of dog 29)of dog 28 which will rotate collar 24 and shaft 13 in a right turn orclockwise direction, thus translating the to and fro wrist movementimparted to sleeve 47 into a. continuous right turn or clockwiserotation of shaft 13 and bit 12.

When it is desired to translate the to and fro or oscillatory wristmovement imparted to sleeve 47 into a continuous left turn orcounterclockwise rotation of shaft 13 and bit 12, the operator moves camwheel 20 into the position of Fig. 3, and thereby slides bar 18rearwardly. This rearward movement of slide bar 18 raises links 32 intheir respective slots 30 while withdrawing the links 32 into theirslots 30 and the dogs 28 and 29 into their respective slots 27 in thecollars 24 and 23, thereby allowing the springs 36 to move the dogs 28and 29 out beyond the peripheries of the collars 24 and 23. Therefore,when sleeve 47 is rotated to the right (clockwise as seen looking fromright to left in the drawing) motion will be imparted by sleeve 47 togear 51, to gears 42, which will rotate gear 53 to the left(counterclockwise), the fingers 52 then riding over the beveled edge(corresponding to beveled edge 56 of dog 29) of dog 28, while one of thefingers 54 abuts the edge 58 of dog 29 and thereby rotates the dog 29',collar 23, shaft 13 and bit 12 to the left (counterclockwise). When theoperator reverses the rotation of sleeve 47 and rotates this sleeve tothe left (counterclockwise looking from right to left in the drawing)the motion of sleeve 47 is imparted to gear 51, to gears 42, to gear 53which is thus rotated clockwise, and the fingers 54 of gear 53 will thenride over the beveled edge 56 of dog 29', while one of the :lingers 52of gear 51 will abut the non-beveled or straight edge (corresponding toedge- 57 of dog 29) f of dog 28 so that the leftward (counterclockwise)motion of gear 51 will be transmitted through dog 28 to collar 24, andto shaft 13, and bit 12 which will thus be rotated continuously in aleft turn or counterclockwise direction, as seen looking from right toleft in the drawing.

From the foregoing description it will therefore be apparent that theinvention provides unique, simple, and conveniently opc erated means fortranslating the oscillatory or to and fro `wrist motion imparted to ascrew driver selectively into either a continuous right turn or leftturn rotation of the driver shaft and bit, while being so arranged thatthe device may be used as a rigid screw driver when so desired.

While I have illustrated and described the preferred form ofconstruction for carrying my invention into eect, this is capable ofvariation and modification without departing from the spirit of theinvention. I, therefore, do not wish to be limited to the precisedetails of construction set forth, but desire to avail myself of suchvariations and modifications as come within the scope of the appendedclaims.

Having thus described my invention, what I claim as new and desire toprotect by Letter-s Patent is:

1. A tool of the character described comprising a rotative shaft, spacedmembers on and fixed to the shaft, a driving gear and a driven gearfloating on the shaft, a slidable member, movable latching elements oneach of the first-named members, elements on said gears projecting overthe first-named members and engageablc with said latching elements tolatch the gears to the first-named members, and means including elementshaving connection with the slidable member for moving said latchingelements into and out of latching engagement with the projectingelementson said gears.

2. A tool of the character described comprising a rotative shaft, a pairof spaced collars on and fixed to the shaft, a driving gear and a drivengear floating on the shaft, a slide bar, spaced elements on said gearsprojecting over the collars, latching elements on each of said collarsmovable into latching engagement with said projecting elements to latchthe gears to the collars, springs urging said latching elements intolatching engagement with said projecting elements, and means havingconnection with the slide bar for moving said pivotal Ielements out oflatching engagement with said projecting elements against the action ofsaid springs.

3. A tool of the character described comprising a rotative shaft, a pairof spaced collars on and fixed to the shaft, a .driving gear and adriven gear floating on the shaft, a slide bar, spaced elements on saidgears projecting over the collars, a pair of latching elem-ents on eachof said collars movable into latching engagement with said projectingelements to latch the gears to the collars, each of said latchingelem-ents having a beveled edge and a straight edge, springs urging saidlatching elements into latching engagement with said projectingelements, and means having connection with the slide bar for movingsimultaneously one of said pivotal elements from each pair thereof outof latching engagement with said projecting elements against the actionof said springs, whereby the projecting` elements on the gears whenrotated in one direction will ride over the beveled edge of saidlatching elements but will engage the straight edges thereof whenrotated in the opposite direction and thereby latch the collars to thegears.

4. A tool of the character described comprising a rotative shaft, a pairof spaced collars on and fixed to the shaft, a driving gear and a drivengear fioating on the shaft, a slide bar, spaced elements on said gearsprojecting over the collars, a pair of latchingelements on each of saidcollars movable into latching engagement with said projecting element-sto latch the gears to the collars, each of said latching elements havinga beveled edge and a straight edge, springs urging said latchingelements intovlatching engagement with said projecting elements, andlinks having connection with the slide bar for moving simultaneously oneof said pivotal elements from each pair thereof out of latehingengagement with said projecting elements yagainst the action of saidsprings, whereby the projecting elements on the gears when rotated inone direction will ride over the beveled edges of said latching elementsbut will engage the straight edges thereof when rotated in the oppositedirection and thereby latch the collars to the gears.

In testimony whereof I aiix my signature.

GUS EDSTROM.

